Contemporary coronary artery bypass grafting surgery is performed on a beating heart to obviate complications commonly associated with prior surgical practices of transitioning a patient onto and off of a heart-lung machine that maintained circulation while the heart was in quiescent condition during construction of a coronary arterial bypass. However, performing an aortotomy and a proximal anastomosis on the aorta that is perfused with blood under pressure contribute to substantial losses of blood in the absence of temporary measures taken to curtail blood flow through the aortic hole. Side-bite and surface-oriented clamping mechanisms have been used to diminish loss of blood during the surgical procedures of punching the aortic hole and anastomosing the graft vessel, but such temporary occlusions damage the endothelium and dislodge emboli that may migrate through the circulatory system. Alternative schemes for performing an aortotomy and limiting loss of blood during the period of anastomosing a bypass graft include introducing a plug or seal at the site of the aortotomy, but such schemes commonly inhibit convenient and rapid completion of the graft anastomosis, and present other complications to be resolved following the grafting procedure.